Estimation and Evidence in Forensic Anthropology: Age‐at‐Death

Abstract

A great deal has previously been written about the use of skeletal morphological changes in estimating ages-at-death. This article looks in particular at the pubic symphysis, as it was historically one of the first regions to be described in the literature on age estimation. Despite the lengthy history, the value of the pubic symphysis in estimating ages and in providing evidence for putative identifications remains unclear. This lack of clarity primarily stems from the fact that rather ad hoc statistical methods have been applied in previous studies. This article presents a statistical analysis of a large data set (n = 1766) of pubic symphyseal scores from multiple contexts, including anatomical collections, war dead, and victims of genocide. The emphasis is in finding statistical methods that will have the correct "coverage.""Coverage" means that if a method has a stated coverage of 50%, then approximately 50% of the individuals in a particular pubic symphyseal stage should have ages that are between the stated age limits, and that approximately 25% should be below the bottom age limit and 25% above the top age limit. In a number of applications it is shown that if an appropriate prior age-at-death distribution is used, then "transition analysis" will provide accurate "coverages," while percentile methods, range methods, and means (+/-standard deviations) will not. Even in cases where there are significant differences in the mean ages-to-transition between populations, the effects on the stated age limits for particular "coverages" are minimal. As a consequence, more emphasis needs to be placed on collecting data on age changes in large samples, rather than focusing on the possibility of inter-population variation in rates of aging.

Cortical bone histomorphology of known‐age skeletons from the Kirsten collection, Stellenbosch university, South Africa

“…The two equations that incorporate On.Ar are the best and worst performers. As with other established methods for estimation of age‐at‐death from the skeleton, we agree with colleagues who have noted, “more emphasis needs to be placed on collecting data on age changes in large samples, rather than focusing on the possibility of inter‐population variation in rates of aging” (Konigsberg et al, 2008; p 541).…”

Estimating age and the likelihood of having attained 18 years of age using mandibular third molars

“…A single individual from one group is not signifi cantly different from any other group, because of the magnitude of the standard deviation and this ethnic difference at the group level is of no consequence when estimating age at the individual level. 37 Results from this study show that methods based on data from South African Blacks 12 and southern China 23 can estimate age with little bias and similar accuracy on our target sample. These fi ndings suggest that features of a reference sample such as size, shape, range of the age distribution and selection of radiographs are more important than the ethnic or geographic group.…”

“…Our understanding of measuring and assessing this has advanced in the last few years with contributions from anthropology, palaeo-anthropology and forensic identifi cation of genocide victims. 37 Measures such as bias, SD of bias, mean absolute difference between dental and known ages, diagnostic tests, and Bayesian statistics are all useful to determine which method is best. 34,37 It is clear from our results that only a handful of methods estimated age with little bias and the two detailed in Table 2 are the recommended methods of choice.…”

“…37 Measures such as bias, SD of bias, mean absolute difference between dental and known ages, diagnostic tests, and Bayesian statistics are all useful to determine which method is best. 34,37 It is clear from our results that only a handful of methods estimated age with little bias and the two detailed in Table 2 are the recommended methods of choice. Few previous studies compare performance of M3 age estimation.…”

A test of the Lamendin method of age estimation in South African canines

“…Recently, much has been written about the choice of a reference sample and its statistical implications when developing age estimation methods [62,63]. Konigsberg et al [63] argued that one may not need population-specific data for age estimates, but rather more data from larger samples.…”